Study Locates Decision Neurons

A new report by a Harvard Medical School (HMS) research team identified specific neurons in macaque monkeys that assign values to different material objects to facilitate decision-making. The results could provide insight into the mechanisms behind human choice.

The report, which appeared in the online edition of the journal Nature on Sunday, located these neurons in an area of the brain known as the orbitofrontal cortex (OFC).

“There are neurons in the orbitofrontal cortex whose activity represents or encodes the value that subjects assign to the available goods when they make choices,” said Camillo Padoa-Schioppa, an HMS research fellow who authored the study along with Associate Professor of Neurobiology John Assad.

According to Padoa-Schioppa, although scientists already knew that decision-making occurred in the OFC because damage in the area resulted in choice deficiencies such as eating disorders and excessive gambling, the new study pinpointed specific neurons involved in the process.

“Our work can potentially be applied to rational and irrational human behavior,” Padoa-Schioppa said.

The study was conducted by testing macaque monkeys’ responses to varying quantities of grape juice and apple juice. They were found to prefer the grape flavor over apple, and larger quantities over smaller ones. When the monkeys were making the choices, specific neurons in the OFC showed increasing levels of activity in correlation to values assigned to each commodity.

Padoa-Schioppa said that there should be many follow up projects to this study with interesting implications, especially when stepping outside the realm of material goods.

“Could the same brain area also be connected to decisions on social goods such as sex? Further research will look at questions like this,” he said.